I think it would be sync issues between clients
Discussion
What are specific sync issues you see?
The most common types are :
some relays don’t appear/aren’t connected (I need to add relays in both clients)
not the same following list (I could be following someone in one client but it will not appear in the other),
notifications aren’t synchronized (I could receive a notification about a reply from one client but it will never appear in the other)